RFR (S): 8079555: REDO - Determining the desired PLAB size adjusts to the the number of threads at the wrong place
thomas.schatzl at oracle.com
Mon Jun 8 10:33:31 UTC 2015
On Fri, 2015-06-05 at 15:34 -0700, sangheon.kim wrote:
> Hi all,
> Please review this REDO change to determine the desired PLAB size for
> current gc worker threads.
> The reason for back out of previous
> change(https://bugs.openjdk.java.net/browse/JDK-8073204) was it wouldn't
> guarantee to be '>= PLAB minimum size'. So added MAX2(min_size(),) to
> guarantee that.
> Currently we calculate an optimal PLAB size with current number of gc
> When the number of workers changes dynamically
> (-XX:+UseDynamicNumberOfGCThreads), the desired PLAB size returned(by
> desired_plab_sz()) is still tuned to the number of gc workers that has
> been used previously.
> This change is, firstly calculate the desired PLAB value for a single gc
> worker and then return desired PLAB size which is bigger(or equal) than
> PLAB min size according to the current number of threads.
looks okay. Can you do a nightly run with the changes in Aurora too,
just in case?
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